In general, a capacitor includes two conductive electrodes on opposing sides of a dielectric or other insulating layer, and may be categorized based on the materials employed to form the electrodes. For example, in a metal-insulator-metal (MIM) capacitor, the electrodes substantially comprise metallic materials. MIM capacitors offer the advantage of a relatively constant value of capacitance over a relatively wide range of voltages applied thereto. MIM capacitors also exhibit a relatively small parasitic resistance.
In integrated circuit designs, on-chip capacitors are used in various applications including dynamic random access memories (DRAM), voltage controlled oscillators (VCO), phase-lock loops, operational amplifiers and other circuit designs. On-chip capacitors are also used to decouple circuits from noise in a separate portion of an electrical system.